When it comes to climate change, clouds are the wild card. Atmospheric physicists at Michigan Tech use a turbulence-generating cloud chamber to better understand the details and droplets.

There are few absolutes in life, but Will Cantrell – professor of physics at Michigan Technological University – says this is one: “Every cloud droplet in Earth’s atmosphere formed on a pre-existing aerosol particle.”

And the way those droplets form – with scarce or plentiful aerosol particles – could have serious implications for weather and climate change.

It’s been known for decades that cleaner clouds tend to have bigger cloud droplets. But through research conducted in Michigan Tech’s cloud chamber, which was published today by Proceedings of the National Academy of Sciences (DOI: www.pnas.org/content/early/2016/11/22/1612686113.full), Cantrell, graduate student Kamal Kant Chandrakar, fellow physics professor Raymond Shaw, and colleagues found that cleaner clouds also have a much wider variability in droplet size. So wide, in fact, that some are large enough to be considered drizzle drops.

The cloud inside the Michigan Tech cloud chamber is turbulent, allowing researchers to keep it for as long as they want, so long as they keep feeding it aerosols. Photo: Michigan Technological University